Massage devices for sexual stimulation are for instance known from the documents U.S. Pat. No. 3,991,751 and U.S. Pat. No. 4,377,692. These are essentially devices replicating the shape and appearance of a male phallus, comprising means integrated therein for generating mechanical vibrations.
In the insofar known massage devices, the means for generating mechanical vibrations typically comprise an electric motor, on the shaft of which a vibration element with an unbalanced mass is attached. Thereby, by rotation of the electric motor, a vibration is generated usually extending orthogonal to the longitudinal extension of the housing, since the shaft of the electric motor is arranged parallel to the housing axis. In the insofar known massage devices, vibrations with relatively high frequency and with low amplitude are produced. Further, a disturbing noise with the frequency of the vibrations occurs in most cases. All this is disadvantageous for the use of the massage device, since this will be regarded as rather annoying.
Massage devices of the type of construction mentioned above are for instance known from the documents DE 29913641 U1, DE 2310862 A and DE 19615557 A1. In the first document above, the means for generating mechanical vibrations are loudspeaker elements, the loudspeaker axis of which is parallel to or coaxial with the cylinder axis of the housing. Because of the use of loudspeakers, the generated vibrations have a relatively high frequency with minimum amplitude in the direction of the cylinder axis. In the subject matter of the DE 19615557, only a front end of the housing is set into vibrations and not the complete housing. Thus, the massage effect is rather low. In the subject matter of the document DE 2310862, the direction of the vibrations is not clear.
For massage devices for the above purposes, it is generally desirable that on the one hand the massage device itself vibrates as a whole, that on the other hand these vibrations have a relatively high amplitude, and finally that the vibrations take place in the directions parallel to the housing axis of the cylindrical housing, since this results in an appreciably improved massage effect. Further, it is desirable that such a massage device can be operated very silently, preferably practically inaudibly.
Various devices comprising vibration generators are known from the documents US 2002/0156402, U.S. Pat. No. 4,697,581, WO2009/152813, CN-2166809, JP-2005-348815, and CN-85205738.